I have at least three google accounts I have access to which I could be signed into at any given time. The one I'm logged into the most frequently is also the one that is not associated with Stack Exchange, since it's shared between several people. Most of the time, this isn't an issue - once I'm logged in to a SE site (using Google as my openID provider), I stay logged in, even when I switch back to the primary google account. However, when creating a new account on a new site, I have to switch to one of my personal accounts, log in with Google's OpenID (which creates the account and associates it), then switch back.

This leads me to a two-part question:

Why can't I create a new account on a new site from an existing
account on another SE site that I'm currently logged into?

Why am I limited to two OpenIDs associated with an account?

The answer to #1 could potentially be "Use a Stack Exchange OpenID" now that that has been added. In fact, I just created one in an attempt to work around this issue, which is when I ran into #2. I already have both OpenIDs in use - I don't have any space to associate a Stack Exchange ID as well. I really don't understand why there's a limit.

Why am I limited to two OpenIDs associated with an account? because they have to set a limit somewhere. Making it open-ended changes things a bit. This is just easier in the long run. Call it architecture design decisions
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jcolebrandJul 11 '11 at 17:26

I would need to disaccociate one of the existing two google accounts to do that, which feels like it'll create more hassle (although that extra hassle just means using the SE login more often, which is not actually a big deal). That will probably be the solution I end up going with.
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BobsonJul 11 '11 at 17:41

@bobson just click "change openid" on your user page to overwrite one of the two credentials..
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Jeff Atwood♦Jul 11 '11 at 17:46

Why can't I create a new account on a new site from an existing account on another SE site that I'm currently logged into?

You should be able to create a new account on an SE account where you don't have one; when you use the same OpenID you are already using on an SE account, the site where you are logging in should notice that and report it to you. The SE site should also associate the new account with the other SE accounts you have.
When I log in to a new SE site, I use the alternative OpenID account, and any SE site notice I used that same OpenID on other SE sites.

It's the way the google client responds to the request. Until you use google's multiple sign in you won't see it. It's kinda odd.
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jcolebrandJul 11 '11 at 17:25

kiamlaluno, it works exactly that way when I'm actually logged into one of the two Google accounts I do have associated, but not when I'm logged into the unassociated (and unassociatable) one.
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BobsonJul 11 '11 at 17:25